Research On Prediction Of Fatigue Strength And Simulation For Foreign Object Damage Of Blade

In order to improve the thrust-weight ratio of the aircraft engine, the edge of the bladebecomes thinner and thinner. And the Foreign Object Damage (FOD for short) can’t be avoidedwith the threat from a variety of hard objects (such as small stone, gravel, bolt rivet etc) for theaircraft engine. Fatigue fracture of blade subjected to FOD can be easily induced with the highcycle fatigue, which may lead to catastrophic accidents. Therefore, it is of great significance to doresearches on FOD simulation and the fatigue strength or residual life of FOD blades.This paper contains three aspects as follows:1、Features of the FOD bladeDamage characteristics of16compressor blades subjected to FOD made from1Cr11Ni2W2MoV were investigated. And damages can be divided into two kinds: dent and notch,and notch is the main form of the damage. The leading edge and trailing edge of blades are thehigh-risk zone where FOD occurs, especially the place higher than the half of blade.2、Research on simulation and fatigue test of FOD bladesUsing the air gun to simulate the FOD blade, then the step-test for high fatigue test ofspecimens are carried out. The research finds that air gun can reflect both macro and microcharacteristics of FOD at a certain extent. The fatigue limit of specimens did not show adecreasing trend with a one-way size increases. Fatigue crack initiate at the notch surface orsub-surface where microscopic damage exists.3、Prediction of Fatigue Strength of FOD bladesFatigue crack growth rate curve of1Cr11Ni2W2MoV specimen at the stress ratio of0.8wasobtained by fatigue crack growth test. The methods of predicting the fatigue strength such asaverage stress modal, fracture modal, field modal and worst case notch modal are reviewed.Results show that the fatigue strength predicted by the Peterson formula is too conservative, andthe value is more accurate by the worst case notch for specimens with FOD.